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Fungal propagule persistence on avocado bolts (small logs) under fruit tree canopies in Florida, USA was assessed for three entomopathogenic fungus-based biopesticides containing Cordyceps javanica, Metarhizium brunneum, or Beauveria bassiana. Bolts were sprayed with a biopesticide or water control to the point of runoff. After drying, four bolts, one from each treatment, were hung randomly under each of three fruit tree canopies in a randomized block design. Bark plug samples were removed from the bolts at 1, 7, 14, and 21 days after treatment (DAT) to determine the persistence of each fungus. Mean numbers of colony-forming units (CFUs) observed in vitro per product were compared. From 1 to 21 DAT, the mean number of CFUs per plate decreased from 100 to 7 for B. bassiana and from 25 to 6 for M. brunneum. However, CFUs of C. javanica increased slightly from 4 to 8. The total mean number of CFUs at 21 days from highest to lowest was B. bassiana > M. brunneum > C. javanica. At 21 DAT, CFUs of C. javanica were observed in plates for the B. bassiana and control treatments, suggesting that C. javanica blastospores may have germinated on the bark and then formed aerial conidia that dispersed to other bolts. Each fungus on the avocado bark was photographed by using scanning electron microscopy. This study demonstrated that EPF-based biopesticides persist for at least 2 weeks on avocado bark in tree canopy shade and are potential biological control agents against ambrosia beetles that attack avocado trees. [ABSTRACT FROM AUTHOR]

Simple Summary: Rhynchophorus ferrugineus is a noxious curculionid species found in date palm and coconut plantations worldwide. Its overall cryptic nature inhibits early detection of infestation symptoms and allows for its rapid expansion. Control methods in plantations usually include single-mode broad-spectrum chemical insecticides to both prevent and mitigate infestations. However, ecological concerns about hazards of both ecosystem and public health, call for safer and more sustainable solutions, including attractants, agronomic approaches, natural enemies and entomopathogenic organisms. This review highlights the published information on the biological traits, host plant spectrum, and management options such as biotechnic and biological control methods like the application of microbial organisms. Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), the red palm weevil (RPW), is a concealed voracious pest of different ornamental and economically important palm species, particularly the date palm. It can cause huge losses in ornamental and commercial palm plantations. RPW has spread rapidly from its original distribution in Southeast Asia to date palm-growing countries worldwide. It is now established in more than 50% of date palm-growing countries and 15% of the coconut-growing countries globally. To prevent further expansion of this pest, many countries have implemented strict legislative and quarantine measures surrounding the export of the palms plant genetic resources from RPW-infested countries. This review focuses on the general biology (life history, development), host range, geographical distribution, and management on the basis of biotechnic methods, farming practices, natural enemies, and important microbial control agents. [ABSTRACT FROM AUTHOR]

Tetranychus urticae (Acari: Tetranychidae) is a widespread and serious mite pest that infests tomato plants and causes economic losses worldwide. We investigated the acaricidal efficacy of two isolates of entomopathogenic fungi (EPF) Metarhizium robertsii (WG-7) and Beauveria bassiana (WG-12) alone and in combination with abamectin when applied topically to tomato leaf discs in the laboratory against T. urticae. We also evaluated the establishment and proliferation of T. urticae mite life stages on tomato plants in the greenhouse after application of each of the above treatments. The combination of abamectin with each EPF caused 100% mortality in T. urticae immatures after 2 days while each EPF or abamectin alone caused moderate mortality, not exceeding 74.2% 3 days post-exposure. Complete (100%) mortality of adults was observed after 5 days in leaf discs treated with M. robertsii plus abamectin whereas B. bassiana plus abamectin caused 100% mortality after 7 days. The mean number of eggs, emerged immatures, and adults were significantly reduced on both sides of the leaves (i.e., abaxial and adaxial sides) after using the combined application of M. robertsii or B. bassiana plus abamectin, compared to abamectin alone and controls. Our results reveal that the acaricidal efficacy of abamectin combined with either EPF was significantly better in managing the T. urticae life stages than either treatment alone under greenhouse conditions. [ABSTRACT FROM AUTHOR]

The Old-World bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae), is a significant threat to crops worldwide and has become resistant to traditional synthetic insecticides. The present study investigated the pathogenicity of the entomopathogenic fungi (EPF) Metarhizium robertsii (Hypocreales: Clavicipitaceae) strain WG-04 or Beauveria bassiana (Hypocreales: Cordycipitaceae) strain WG-10, and an entomopathogenic nematode (EPN) species Heterorhabditis bacteriophora against the second and fourth instar larvae of H. armigera. Both fungal species and H. bacteriophora were evaluated, singly or in combination. After 24 and 48 h post-application of the fungal spores (106 spores/mL), H. bacteriophora was introduced at a rate of 50 infective juveniles/mL, and mortality was observed at 3-, 5-, and 7-days post-treatment. Adult emergence, egg hatching, and percentage pupation were recorded. The integration of both types of biocontrol agents exhibited additive and synergistic interactions in larval stages, and enhanced mortality was recorded when EPF was used in combination with the nematodes. In the individual application of all three biocontrol agents alone, the order of efficacy was H. bacteriophora > B. bassiana > M. robertsii; however, in joint treatments, the increase in mortality and decrease in percentage egg hatching, pupation, and adult emergence was determined to be directly linked to the exposure period of the H. bacteriophora. The results of this study suggest that combining H. bacteriophora with EPF could provide a solid foundation for an economically viable method for managing H. armigera larvae in chickpea fields. [ABSTRACT FROM AUTHOR]

The commercial fungal biopesticide product PFR-97 20% WDG, based on the entomopathogenic fungus Cordyceps fumosorosea (Cfr), is registered in the U.S.A. for foliar sprays on citrus. The persistence of Cfr suspensions (107 blastospores/mL) applied to grapefruit plants was evaluated under summer field conditions in southern Florida. Concurrently leaf disk bioassays were conducted to evaluate the pathogenicity of fungal residues on field-aged leaves against the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. The results demonstrated that Cfr persisted for at least 35 days under our field conditions and caused up to 40% ACP mortality when used in bioassays. There was a general trend of higher colony forming unit counts and a correspondingly higher ACP mortality with the residue age of field-treated leaves. We hypothesise that under certain environmental conditions the Cfr propagule residues will germinate, produce hyphae, phialides and develop conidia on the leaf phylloplane over time. During this study, an adult citrus leafminer Phyllocnistis citrella (Stainton), another important pest of citrus was observed mycosed with Cfr hyphae and subsequently attached to the citrus leaf. Our study shows that Cfr can potentially provide supplemental longer-term management for ACP. Abiotic and biotic factors that may affect the field activity of Cfr and other mycoinsecticides over time are discussed. [ABSTRACT FROM AUTHOR]

Mesh exclusion bags are increasingly being adopted by Florida citrus growers to protect young citrus trees from Asian citrus psyllid, Diaphorina citri Kuwayama, and Huanglongbing disease. These mesh bags exclude larger insects such as D. citri but may allow entry of minute insects. Hibiscus mealybugs, Nipaecoccus viridis (Newstead), have been observed thriving in the micro-habitat created by these covers on trees. Entomopathogenic fungi (EPF) and insect growth regulators (IGRs) are effective against several mealybug species under various growing conditions, but their efficacy against N. viridis or within the microclimate within exclusion bags is unknown. Therefore, we evaluated various formulations of entomopathogenic fungi with and without IGR against N. viridis using laboratory bioassays. We then conducted semifield bioassays to determine effectiveness of EPF formulations alone and in combination with an IGR applied to citrus trees enveloped within mesh bags under field conditions. Survival probabilities of N. viridis nymphs exposed to all Beauveria bassiana-based products tested were comparable to malathion under laboratory conditions and reduced survival as compared to controls (water only). Under field conditions, mortality of N. viridis nymphs on leaves sprayed with each fungal formulation tested was significantly greater than on control treatments (Water, Suffoil X, 435 oil) up to four weeks post application. There were no differences in the colony forming units per leaf area amongst all fungal treatments. Formulated B. bassiana-based products applied alone or combined with an IGR should be effective tools for managing N. viridis populations on young citrus trees protected with mesh exclusion bags. [ABSTRACT FROM AUTHOR]